Tehran University Medical Journal

Normal 0 false false false EN-GB X-NONE AR-SA MicrosoftInternetExplorer4 Background: The ability of a specific test to predict a difficult intubation is decreased by the variability of definitions of difficult intubation/laryngoscopy. The Mallampati classification system is a widely utilized approach for evaluating patients in the preoperative setting. Zero class of Mallampati is a new class of airway view that to add to the four modified Mallampati classes. This study estimates the incidence of class zero airway and determines the ability of Mallampati score, age and sex on the prediction of the larangoscopy grade.
Methods: This is a cross sectional study in which 376 patients aged 7-18 years and A.S.A physical status I or II were enrolled. They were scheduled for surgery under general anesthesia All the airway assessments were done in the sitting position, with the patient's head in neutral position, mouth fully open, tongue fully extended and without phonation. After induction of general anesthesia, laryngoscopy grade was assessed in sniffing position using the Cormak & Lehame grading scale.
Results: Class zero airways occurred in 0.3% of patients, and the patients with class zero airway had a grade I laryngoscopy. 49.5% of patient had class I, 37.2% class II, 13% of patient had class III and there found no patient with class IV airway. Grade II and III laryngoscopy were more frequent in females than in males but this correlation was not statistically significant. 
Conclusions: Assessment of airway by Mallampati scoring system and attention to the age can be an important factor in the prediction of high laryngoscopy grade.

Background: Inadequate ventilation, esophageal intubation and difficult intubation are the most common adverse respiratory outcomes in patient undergoing anesthesia .The aim of this study was to compare Mallampati test in supine and sitting positions in traditional approach and during phonation for predicting difficult laryngoscopy and intubation.
Methods: In this study performed in Imam Khomeini Hospital in Tehran, Iran, Mallampati test was performed on 661 patients who met the inclusion criteria for the study. The test was done in supine and sitting positions with and without phonation by a rater who was blind to Mallampati test. Subsequently, laryngoscopy view and difficult intubation were evaluated in the four aforesaid positions by Mallampati test for predicting difficult laryngoscopy and intubation. For each situations, sensitivity, specificity, positive and negative predictive values and accuracy were calculated.
Results: Overall, 28 (4.2%) patients had difficult laryngoscopy and 9 (1.4%) patients had difficult intubation. The highest sensitivity for Mallampati test in predicting difficult laryngoscopy and intubation was in supine and sitting positions without phonation, and the highest specificity was seen in sitting position with phonation. Negative predictive values were more than 95% in all different positions for Mallampati tests and the highest positive predictive value was seen in supine position with phonation.
Conclusion: According to our findings, the highest correlation between Mallampati test and different positions in predicting difficult laryngoscopy and intubation was seen in supine position with phonation. Phonation improved Mallampati score in supine rather than sitting position.